Delayed arming mechanism



Dec. 22, 1953 P. H. THOMPSON 2,663,260

DELAYED ARMING MECHANISM 2 Sheets-Sheet 1 n J l- Filed Jan. 8, 1952 i T INVENTOR. 4 8 I i 4 Parke Thun-Faun B59, MQW@ Dec. 22, 1953 P. H. THOMPSON DELAYED ARMING MECHANISM Filed Jan. 8, 1952 2 Sheets-Sheet 2 Patented Dec. 22, 1953 FFIC y 2,663,260 DELAYED ARMING MECHANISM Parke H. Thompson, Kirkwood, Mo., assigner to United States of America as represented by the Secretary of the Army Application January 8, 1952, Serial No. 265,444

15 Claims. (Cl. 102-79) The present invention relates to a delay arming device for a projectile fuse.

The use of delay arming devices in fuses foi` explosive and incendiary projectiles are well known in the art. Such delay arming devices are provided to maintain the fuse safely unarmed while the projectile is traversing the bore of the weapon, and for a predetermined time thereafter to prevent premature explosions which would endanger the lives of operating personnel in the gun crew, and could also lead to the destruction of the weapon from which the projectile is iired. In addition premature explosions would also endanger friendly personnel in forward battery positions and would obviously render considerably less effective the striking force of an attacking unit due to the decrease in the number of projectiles exploding upon the selected target. Delay arming devices of the kind found m the prior art usually involve mechanism which is armed by means responsive to rotation of a projectile or to linear acceleration of a nonrotating projectile, as for example arming blocks movable into position by linearly or centrifugally responsive gear trains, centrifugal arming ball rotors etc.

It is accordingly a specic object of this invention to provide a delay arming device for a fuse which maintains the fuse elements in unarmed position for a predetermined interval of time suiiicient to permit the projectile to clear the gun, and to travel to a safe location.

A more specic object of this invention is to provide a delay arming device for a rotating projectile including an arming ball rotor which is movable into armed position by mechanical means actuated by a centrifugally responsive substantially toroidal expansible spring.

Another object of this invention is a similar delay arming device for a non-rotating projectile wherein the toroidal spring is torque loaded or prestressed as by winding, in order to move the arming ball rotor into armed position upon release of the spring by means responsive to linear acceleration.

Another further object of this invention is to provide a delay arming mechanism in a fuse, including a housing and cover having allochirally mated concavities to complete a spheroidal cavity for receiving a metal ball rotor, wherein means are provided in the cover to engage and move the ball rotor into armed position under the action of a substantially toroidal spring which is joined at opposite ends to the cover and to the main fuse body.

With these and other objects in View which will appear as the following speciiication develops, reference is made to the accompanying .drawing wherein like numerals are used to desig- 2 nate corresponding or similar parts in the several views and wherein:

Figure l is a longitudinal section of the fuse body with the metal ball rotor and movable parte` in unarmed position.

Figure 2 is a fragmentary section similar to Figure l but with the ball rotor and moving parts in armed position.

Figure 3 is a view showing respectively, from left to right, the housing and concavity, the metal ball rotor, and the cover with mating concavity.

Figure 4 is a transversesection taken on line 4 4 of Figure 2.

Figure 5 is a section looking in the direction of arrows 5 5 of Figure 2 and showing details of the escapement lever or pawl.

Figure 6 is a section looking in the direction of arrows 6 6 of Figure 2, and showing details of the cover including the interdental spaces which coact with the pallets on the escapement pawl.

Figure 7 is a longitudinal section of a modiiication of the delay arming device (assembled), wherein the escapement pawl and associated parts are located within the housing.

Figure 8 is a section taken on line 8 8 of Figure 7.

Figure 9 is a View on line 9 9 of Figure 8 looking in the direction of the arrows.

Figure 10 is a View on line Ill I0 of Figure 8 looking in the direction of the arrows.

Referring more particularly to Figures l and 2, I designates the main body of the projectile of the point-detonating type, peripherally recessed at 2 to accommodate the nose portion 3 to complete the forward ogive of the projectile. The main body portion I has an axial bore 4 which is stepped as at 5 and enlarges rearwardly into a counterbore 6 which forms the main eX'- plosive or incendiary charge container, as is well known, to receive a charge l. A cup-shaped member 8 is press fitted into bore 4, a portion of this cup extending rearwardly into counterbore 6, as at 9, to serve as a container for receiving a booster charge I0.

The delay arming device per se comprises a cylindrical core II, which is shaped like an E 1n cross section to form an annular chamber I2 between the legs and central portion thereof. Core II is tightly press tted into cup-member 8 with its rearward face spaced from the bottom of the cup member 8 to form the before-mentioned booster charge receiving space 9. An axlal counterbore I3 is formed in the central portion of core II to serve as a housing IIc for an arming ball rotor I4, the central portion of the rear Wall of counterbore I3 being dished out as at I5 to form a spherical cavity upon which 1s seated for rotation thereon the rotoi` I4. Spherical cavity I5 is centrally apertured as it In order to prevent the escapement lever from turning relative to housing l la, there is provided a forwardly directed pin IIb made integral with housing l la and extending from the bottom wall of counterbore I3' into a longitudinal bore 361 in escapement pawl 36', when the device is assembled.

The delay arming device is provided with a cover 25 which has a rearwardly reduced portion to fit into and slidably engage the inner wall of counterbore i3. The cover is provided with a counterbore 2519 opening rearwardly into counterbore i3' and the forward wall of counterbore 2519 is dished out centrally as at 2l to form a spherical seat, for rotor I4', allochirally mated with seat V5 in housing lla, and which with seat I5 and cylindrical bore 36o in the escapement pawl completes the substantially spheroidal cavity in which arming ball rotor le rotates.

rIhe escapement means for this modication is similar in action to the one provided for the species illustrated by Figures 1-6, but is slightly different in design. The pallets 35 on the forward face of the escapement pawl, instead of being pyramidal, are semi-spherical bosses spaced 186 apart, on an axis normal to the axis upon which the pawl rocks. The rearward flat surface of the cover is provided with a plurality of closely spaced equiangularly disposed semi-spherical holes Si axially concentric with respect to the cover per se, and which are perimably engaged by the pallets as the lever oscillates and the cover rotates.

An odd number of holes are provided in the cover, so that coaction between the spherical bosses and spherical cavities is the same as that between the pyramidal pallets and gear teeth of the first described species, wherefore one pallet will move toward engagement while the other progresses toward release. Movement of the cover, similarly, is provided by a coil spring (not shown) surrounding the cover, which is expansible in response to centrifugal force or which may be prestressed as by winding the cover, to turn the cover when it is released by linear acceleration or deceleration. The cover is also provided with a setting pin 28 made integral therewith and extending rearwardly and inwardly into an arcuate peripheral slot 29 in arming ball rotor hi. As previously explained the contour of the slot is such that as the cover rotates through an angle of 18o degrees about the longitudinal axis 0f the device, arming ball rotor I4' rotates, as a result of the pressure applied by the setting pin, through an angle of 90 degrees in a plane of motion normal to the plane of -motion of the cover, to place the axis of detonating capsule 24 in coincidence with the longitudinal axis of the device, to thereby arm the fuse.

Operation Driving torque is supplied by coil power spring 3S. While the projectile is at rest the spring, being unstressed, exerts no torque. When the projectile is fired and is caused to rotate by the means provided for that purpose, spring 30 is expanded by centrifugal force, moving outward in chamber l2 from its initial position against rotor cover 25 until it seats against the cylindrical surface of chamber l2. In this position the spring exerts a torque on the rotor cover causing it to rotate through an angular displacement of 180 within an interval of time determined by the oscillating characteristics of the escapement lever. The lever will rock on its pivots so that one pallet moves toward engagement While the other pallet progresses toward release. The motion of rotation is transmitted from the rotor cover to the rotor through the setting pin and arcuate slot, and the rotor is brought to armed position in the manner previously described.

It is within the scope of this invention to also make the delayed arming mech-anism and escapement means, above described, applicable to a non-rotating projectile. In this modification some well known winding means may be associated with the cover to turn it a predetermined amount to prestress the coil spring. A release will be provided which may be a pin mounted in the fuse body and effective to engage and lock the cover after winding, so that the ball rotor is in unarmed position. lIn response either to linear acceleration or deceleration, the pin will release the cover so that the prestressed spring will cause it to rotate. The escapement lever will act similarly as above described, while the rotor is being moved into armed position.

Other modications and alterations of the structure which has been disclosed herein for purposes of illustration will be apparent to those skilled in the art, and it is obvious that the same may be made without departing from the spirit and scope of the invention as defined in the following claims.

I claim:

1. A delay arming device for projectile fuses comprising, a housing having an axial counterbore, an arming ball rotor in said counterbore rotatable from first unarmed position to second armed position and having an arcuate peripheral slot, a cover for said housing, a setting pin integral with said cover extending into said rotor slot, means to turn said cover relative to said housing whereby said pin rotates said ball rotor, and escapement means associated with said cover to provide timed motion for arming said ball rotor.

2. The combination in claim 1 wherein said means to turn said cover comprises an expansible member having one end secured to said housing and a second end secured to said cover.

3. The combination in claim 2 wherein said expansible member expands in response to centrifugal force to turn said cover.

4. The combination in claim 3 wherein said escapement means includes a peripheral bevel formed in the forward surface of said cover, a plurality of serrations formed in said beveled surface, an escapement lever pivotally mounted in said housing and having a rearward surface adj acent to and substantially parallel with the forward surface of said cover, and a plurality of pallets on said escapement lever surface interdentally engaging said serrations.

5. A delay arming device for a rotating projectile fuse comprising a housing, an arming ball rotor in said housing rotatable from first unarmed position to second armed position and having an arcuate peripheral slot, a cover for housing, a setting pin integral with said cover and extending into said peripheral slot, means responsive to centrifugal force to turn said cover relative to said housing and said rotor relative to said cover, and escapement means in said fuse associated with said cover to provide timed motion for arm- ;ing said ball rotor.

6. The combination in claim 5 wherein said centrifugal force responsive means comprises an expansible coil spring surrounding said cover and having one end secured to said cover and a lsecond end secured kto :said housing.

. 'I'he combination in claim 6 wherein said apement means includes a peripheral bevel med in the forward surface of said cover, a rality of gear teeth formed in said bevel sure, an escapement lever pivotally mounted in :i housing and having a rearward surface adent to and substantially parallel with the ward surface of said cover, and a plurality of lets on said escapement lever surface interitally engaging said gear teeth. l. A delay arming device for a projectile fuse uprising a housing, an arming ball rotor in d housing rotatable from first unarmed posiu to second armed position, means including otatable cover for said Vhousing engaging said l rotor to rotate the same, and escapement ans engaging said cover constructed and ar iged to provide time motion for arming said .l rotor. The combination in claim 8 wherein said 2O lans to rotate said ball rotor includes a coil ing having one end secured to said housing d the other end secured to said cover means d expansible in response to centrifugal force. LO. A delay arming device for fuses for rotat- 5 projectiles comprising a housing symmetrical out a longitudinal axis and having an axial mterbore, an arming ball rotor in .said interbore rotatable from iirst unarmed posiin to second armed position, a pivot pin 'in .said 30 using extending into a drilled cavity 'in said tor to provide an axis of rotation for said rotor rmal to 'said Ilongitudinal axis, said rotor hav g an arcuate peripheral slot, a cover slidably gaging said housing, a setting pin in said cover tending into said peripheral slot, 'means to rn said cover 'relative to 'said housing whereby id setting pin Vrota-tes said ball relative to said ver, said means comprising a power spring iled about said cover having one end secured o saidhousing and a second end secured to said ver, said 'spring 'being expansible in response :centrifugal 'force' Ato 'turn `said cover, and capem'ent 'means in -said 'fuse associated 'with id cover to provide timed motion for arming id ball rotor. l1. The combination in claim '10 wherein said capemen't Vmeans includes a peripheral 'bevel rmed in the forward 'surface of said cover, la urality of 'gear teeth )formed in ysaid beveled riacc, an 'escapemen't lever piVo'ta-ily mounted "50 said 'fuse and having Aa rearward surface -ad- `cent rto and substantially parallel with the for ard 'surface l'of said cover, and a plurality of tllets 4on said -escapement glever interdenta'lly igaging said gear teeth. 55

12. Adelay arming device for -fuses -for rotating rojectiles comprising --a-cylindrical 4housing sym-- .etrical about a longitudinal -axis'and-havling an rial counterbore, f-aniarming ball rotor in "conguous relation .with lthe walls -of said counterire rotatable through '90 degrees Iirom-'iirst un- ."med position yto second armed position, said ill @rotor Ihaving a -diametral :bore to receive a etonator with Ian Laxis normal to said longiidinal iaxis when said vfuse iis unarmed .and 'w65 )incident 'with Csaid longitudinal :axis whenssaid ise xis armed, i-said :housing YYhaving apivot pin rtending into a fdrilled cavity insaid Irotor eto rovideY an axis fofLrotation for saidlrotor normal i said longitudinal axis and to :fsai'd .detonator :70 xis, said rotor having :an farcuate :peripheral Lot, :a "cylindrical :'cover :'slidably engaging said ousing, fa settingpin :protruding inwardly a from iid -coverfv and extending into "said ..arcuate islet, ieans in response Lto centrifugalforceto.rotate ".75

said cover relative to said housing about said longitudinal axis whereby said setting pin rotates said ball rotor relative to said cover, said means comprising a coil spring encircling said cover in unarmed position and expansible in response to centrifugal force, said spring having one end secured to said housing and the other end secured to said cover, and escapement means in said fuse adapted to cooperate with said cover to provide timed motion in rotating said ball rotor into armed position.

13. The combination in claim 12 wherein said escapement means comprises a peripheral bevel formed in the forward surface of said cover, an odd number of equally spaced gear teeth distributed about said beveled surface, an escapement lever pivotally mounted in diametrically opposed bearings in said fuse on an axis normal to said longitudinal axis, said lever having a substantially cylindrical central portion with its rear face adjacent to and parallel with the -forward face of said cover, a pair of diametrically opposed pallets formed on the rear race of said lever on an axis normal to the axis of pivot of said rotor, each said pallet alternately interdentally engaging said gear teeth as said cover rotates to thereby provide timed motion for arming said ball rotor.

14. A delay arming device for a projectile fuse comprising .a housing `having an axial counterbore, a cylindrical escapement pawl in ,said counterbore mounted for rocking motion about an axis normal to the longitudinal axis of said housing, said pawl having an axial substantially cylindrical bore, ya cover for said housing having .a flange slidably engaging the wall of said counterbore for rotation labout the longitudinal axis of said housing, a ball rotor received in the bore of said .escapement pawl `and pivotally mounted for rotation about an axis normal to the longitudinal axis of said housing ,and in a plane of motion normal to the plane of motion of said cover, a setting 'pin integral with said housing and extending into an arcuate peripheral slot in said ball rotor,V a pair of semi-spherical pallets diametrally Vsecured on the forward face o'f said 'escapement pawl, each alternately perimably engaging `semi-spherical holes yformed concentrically about ythe Alongitudinal axis o1" said cover and `on the rearward face of said cover, when said y'cover turns, and a coil spring having one end connected to said -cover and the other end to said housing, responsive to acceleration of said projectile to turn-said cover whereby said ball rotor yrotates in time motion -into yarming position.

.15. Thecombination yin claim 14 including a diametral -bore in Vsaid rotor, a detonator in said diainetral bore with axis llying crosswise of the longitudinal axis ofsaid'housing, when said 'fuse `is unarmed and movable into coincidence with said longitudinal axis to arm said fuse.

H. THOMPSON.

References .Cited in the file of this patent 'UNITED `STATES PATENTS Number Name Date 1,774,043 Summerbell Aug. 26, 1930 234353415 Thompson Feb. 3, 1948 2,53*(953 Andrews Jan.,1 6, 1951 Y FOREIGN PATENTS Number Country Date 257,335 GreatlBritain Aug.'2 7, 1926 $1 051 ;GreatBritain '-May-26, 1899 

